Ophthalmic-lens blank



, I919- 1,340,02 1 I Patented May 11, 1920.

ENTOR ANDREW JAY CROSS, on NEW YORK, N. Y.

OPHTHALMIC-LENS BLANK.

Application filed April 29,

T 0 all whom it may concern:

Be it known that I',- A1-iomnw JAY CRoss,

.a citizen of the United States, and a resident of the city, county, and State of New York,

have invented a new and useful Improvement in Ophthalmic-Lens Blanks, of which the following is a full, clear, and exact description. i

My invention relates to improvements in lens blanks such as are delivered to lens grinders ready to be ground, polished, and finished into lenses of desired values or. powers. More, particularly my invention relates to combination ophthalmic lenses having areas of different powers, and the general object of my invention is to produce a blank which can be more readily and accurately finished by a local grinder than the ordinary blanks, and to provide a blank having one member entirely finished on one surface and of a certain. definite value, which will serve as a base, and the rest of the lens can be ground as desired and so as to correspond in a desired way with this finished part ofthe blank. The demand for peculiar types of modern ophthalmic lenses -covering spherical, cylindrical and pris ma'tic values in multiple independent quantities, has led to the production of partially ground glass blanks which local lens grind ers can finish in varying focal strengths.

Heretofore, however, these focal powers have' been somewhat limited, demanding many blanks in order to have a complete assortment of numbers. In my improved blank the manner of its construction covers awide range of possible lens combinations as well as presenting possibilities for the control. of independent optical centering of its various focal areas, as will be seen from the description which follows.

In the drawings I have shown a two member blank in which what isdestined to be a close vision member has its inner surface ground, polished and finished, while the rest of the blank is comparatively in the rough. The two members are fused together edge to edge in a way to present a substantially perfect union, and as will appear the blank can be ground to the desired value, or so as to have areas of desired values with reference to the finished part of the blank.

Reference is to be had to the accompanying drawings forming a part of this specifispecifieation or iaen Patented May 11, 1920.

191a sexm1 110.2%,430.

cation, in which similar reference characters indicate corresponding parts 1n all the views.

tion blank embodying my invention.

' Fig, 2.is a cross section of the same".

Fig. 3' is an elevation and cross section of the main part of the blanlg, and

Fig. 4; is an elevation and cross section, of the member which has oneisurface finished.

The major member 10 lot the blank is unground on both surfaces and has a segment cut away as shown at 11 and the edge 12 of'this segment is accurately ground so as to giveit a surface of revolution, that mares at right angles to each other, and

has therefore compound or toroidal curve The member 13 has one edge 14- correspond Figure 1 isanelevation of the combinaingly ground so that it can be" fused permnently and nicely to the edge 1'2 of the major member 10, and this is done so as to leave the outer. surface flush (with the outer surface of the major member 10, while the inner surface of me maj'or member 10 substantially overhangs the member 13 as the' drawing shows. The inner surface 15 of the minor member 13 is entirely finished] ready for use and of a predetermined value. The blank is made up as described with the members 10 and 13 fused together as specified,'-and when shipped a dummy 16 of glass is slipped into the segment 11 so as to cover the finished surface 15 'of-the member 13, and it is temporarilycemented to the member 13 by balsam-or the like. A local lens grinder can, therefore, grind both surfaces of the major member 10 to the desired extent and shape so as to produce one or more lenticular areas thereon, and the dummy 16 still remains in place until the lens is finished, when the dummy will be ground to the thinnest wafer, but will meanwhile have served its purpose of protecting the finished surface 15 of the member 13'. \Vhen the lens is finished the dummy is removed in and finished, and the outer surfaces of the members 10 and 13 and the inner surface of the member 10 can be ground to the desired values with reference to the basic or finished surface 15.

I claim 1. As an improved article of manufacture, an ophthalmic lens blank comprising two members one thicker than the other, fused together edge to edge into an integral whole, the thicker member being unground on its two surfaces, the other or thinner member having one of its surfaces unground and the other surface finished and polished before fusing, the two members joining one another in such a manner that the thicker of the two members will overhang the edge of the thinner.

2. An ophthalmic lens blank comprising two members of different thicknesses fused together edge to edge, the thicker of said members having both major surfaces unground and the edge to which the thinner member is fused finished, and the thinner of said members having one surface finished anbone unground, also-its edge finlshed.

3. An-ophthalm1c lens blank comprising an ungrmindmember having a segment emoved and the edge from which said egment is removed finished, a second thinner meml'mrfitting in said segment edge to edge with the first member and fused thereto, the second member having its outer surface ungrouml and its inner surface finished, also its edge finished.

4. An ophthalmic lens blank comprising a major unground member having a segment removed and withthe edge where said segment is removed finished, a minor member fitting in the aforesaid segment finished and fused edge to edge to the major member, and a dummy removably cemented to the blank and fitting against the finished surface of the minor member. 7

ANDREW JAY CROSS.

Witnesses v WARREN B. HUTOHINSON, M. G. ODONNELIm 

